Antigen testing to be deployed in addition to PCR as numbers rise

A lab technician holds a Healgen Covid-19 Rapid Antigen Test at RocDoc's testing facility in Gorey, Co. Wexford. Picture Brian Lawless

The HSE’s national lead for testing and tracing, Niamh O’Beirne has said that antigen testing will be deployed in addition to PCR testing as the number of people presenting for testing rises.

Ms O’Beirne told RTÉ radio’s Today with Claire Byrne show that antigen testing will be used for close contacts who will have to self-test four times, on days zero, five, seven and ten. Those people will also have to self isolate.

There had been a significant rise in the numbers presenting for testing at community testing sites in recent days, she said with an average positivity rate of 5.9%, rising to 15% in some locations. This compared with positivity rates of up to 50% last January, she explained.

At present, the highest positivity rates were in Roscommon, Donegal, Wicklow, Cavan, Louth, Monaghan with the majority in the 21 years to 30 years age group.

Ms Beirne said that much of their planning relied on NPHET’s modelling which allowed her teams to prepare to step up capacity as required. Some of the possible scenarios were “very startling” she acknowledged.

Niamh O’Beirne, National Lead, Testing and Tracing

If the level of demand for testing were to rise to 120,000 per day PCR testing would not be possible which meant that plans this time included antigen testing for close contacts. A box of five antigen tests would be sent to each close contact and their results would be monitored.

The demand for tests will increase in the next two weeks, she said. The initial “lift” in numbers had been higher than modelled.

In January, even though the numbers were very high, all close contacts had been contacted, she said, even on the worst days when they were coping with 6,000 to 7,000 cases, however, the calls to those contacts were of a shorter duration, to allow more calls to be made.

Pop up centres would be deployed to bigger testing centres on busy swabbing days, said Ms O’Beirne as it was more effective to test 500 people at a bigger testing site than 19 in a smaller location. If there was a surge in a village then people would be directed to a larger mass testing centre.

Ms O’Beirne encouraged the public to continue to use the Covid App and to “tell us all their contacts” as it was now known that people had more contacts.

The vaccination programme was helping the situation, she added. “It is the unvaccinated that are contracting the virus.” Of the 107 outbreaks in the last week, two were in hotels, while the previous week hotels accounted for eight of 121 outbreaks, she said. Most of the outbreaks were from group settings, house parties, family gatherings with travel cases on the increase, she said.

Travel accounts for approximately 10% of cases at present, she said. “Flights are complex for us,” as manifests, travel locator forms all have to be followed up. The number one cause is close contacts, flights are second and social gatherings are third, she added.

The HSE had a supply of antigen testing kits ready if required to be deployed, while testing and tracing will be able to adjust their capacity to cope with 15,000 to 16,000 calls per day, she said.